<html>

<head>
    <title>Canvas tutorial</title>
    <style type="text/css">
    canvas {
        border: 1px solid black;
    }

    body {
        background: rgb(50, 54, 57);
    }
    </style>
</head>

<body>
   <body onload="main()">
   	<p>99999</p>
   	<p>99999</p>
   	<p>99999</p>
   	<p>99999</p>
   	<p>99999</p>
  <canvas id="glcanvas" width="640" height="480" style="position: absolute;top:0;left: 0">
    Your browser doesn't appear to support the HTML5 <code>&lt;canvas&gt;</code> element.
  </canvas>
</body>
</body>
<script type="text/javascript">
 
 //
 // start here
 //
 function main() {
   const canvas = document.querySelector("#glcanvas");
   // Initialize the GL context
   const gl = canvas.getContext("webgl");

   // Only continue if WebGL is available and working
   if (!gl) {
     alert("Unable to initialize WebGL. Your browser or machine may not support it.");
     return;
   }

   // Set clear color to black, fully opaque
   gl.clearColor(1, 0.0, .2, 1);
   // Clear the color buffer with specified clear color
   gl.clear(gl.COLOR_BUFFER_BIT);
 }
</script>

</html>